The HNIW/FOX-7-based PBX has been aged 7， 14， 21 d and 28 d at 71 ℃ according to GJB736.8-90 initiators and pyrotechnics test method， respectively. And the morphology and thermal decomposition properties of PBX molding powder before and after aging were characterized. The PBX molding powder was tested by FTIR and XRD. The variations of size， mass and mechanical properties of the PBX columns have been measured before and after aging tests. Results show that the mass and size change rate are both within 1%， which meets the evaluation standard of MIL-STD-1751， indicating that PBX columns are still at an acceptable level after aging tests. The surface morphology of PBX molding powders has changed in varying degrees. There are more surface cracks and the surface morphology are more uneven with the increase of aging time. Moreover， FTIR and XRD results indicate that the molecular structure and crystal form of HNIW/FOX-based PBX have not changed after aging tests. Besides， the analyses of thermal decomposition performance show that the thermal decomposition activation energy of PBX molding powders have decreased after aging tests with the decreases of -5.23%， -5.88%， -7.00% and -8.23%， respectively， which demonstrates that PBX still has good thermal stability after aging tests. The results of mechanical properties show that the compressive strength of HNIW/FOX-7-based PBX increases by 3.18， 3.40， 3.67 MPa and 3.79 MPa， respectively， and the modulus increases by 0.65， 0.79， 0.91 GPa and 0.96 GPa respectively after aging for 7， 14， 21 d and 28 d. Therefore， the change rate of compressive strength and elastic modulus of PBX columns are positively correlated with the aging time， indicating that the compressive strength of PBX columns increases after aging test.